Power scalable and efficient 790nm pumped Tm3+-doped fibre lasers

This paper presents a discussion of the engineering issues and results of high power 2 mu m Tm3+-doped fibre lasers pumped at 790nm. To date we have achieved up to 85W from such devices with 54% slope, efficiency relative to launched pump.(1) More recently, through using Tm3+ concentrations of approximately 4(wt.)% to,3 3-s of up to enhance the cross-relaxation process (H-3(4),H-3(6) -> F-3(4) F-3(4)) we have demonstrated slope efficiencie 67% relative to launched power. This represented similar to 170% quantum slope efficiency for the 790nm pumped 2 mu m laser.